Abstract: A device for testing the tightness of fit of a gas mask which has a tubular respiratory air inlet and a tubular exhaling air outlet, which is applied over the face of a wearer, comprises a bag-like headpiece which is engageable over the wearer's head and is preferably made of a transparent material, such as plastic, and which is provided with an opening for the wearer's neck and an opening for the tubular air inlet of the gas mask with a resilient rim for tightly engaging these parts when the headpiece is positioned on the wearer's head. The headpiece also includes a tubular exhaling air connection piece which is formed on the interior of the headpiece in a position to be engaged over the tubular exhaling air outlet of the gas mask. The connection piece includes an uptake passage for the passage of air directly from the mask outwardly through the passage.

Abstract: A respiratory device coupling construction comprises a device which is used for respiration and which contains a cylindrical receiving recess for a connection such as a breathing gas connection. The connection or coupling includes a connector for a conduit of the gas which has a tubular portion which is insertable into the receiving recess. A tubular cover member overlies the cylindrical receiving portion and has a slot therethrough. A U-shaped locking spring has a web portion with an actuating part which is displaceably positionable in the slot so as to project from the cover member for engagement by a person's hand. The U-shaped locking spring includes two leg portions which straddle the tubular portion. Respective legs engage in respective slots on diametrically opposite sides of the tubular portion of the connecting device and the ends of these legs engage against a camming surface defined at the edge of the slot on the tubular portion.

Abstract: A protective helmet and a full face mask for combined use on the head and face of a person, comprises a mask which is adapted to fit over the face and has a peripheral portion for encircling the chin, jaws and forehead of the face. The helmet engages over the person's head and has at least one portion adapted to overlie an edge of the mask. The mask has a receiving bearing recess in the overlying portion of the helmet and the helmet has a locking mechanism which comprises a member which is rotatably mounted on the helmet and has a pin which is slidable toward and away from the recess. The pin is urged under spring action into the recess and, when the member is rotated, the pin rides in the recess to pull the mask toward the helmet and toward tighter engagement with the person's head.

Abstract: A protective breathing device comprises a housing having a filter therein and with an inlet air passage through the filter and through an internal passage in the housing to a breathing tube having a mouthpiece which is adapted to be fitted to the wearer. The breathing tube includes an exhaling valve for expelling air which is exhaled through the breathing tube. The housing carries an oxygen cartridge which is fired or opened by a firing pin which penetrates the cartridge in order to supply oxygen into the housing passage for flow through the breathing tube when this is necessary. In addition, the housing has an annular chamber surrounding the inhalation duct carrying an economy bag through which portions of the exhaled air may be recirculated for flow back into the breathing tube on a successive respiration in order to maintain the oxygen content within acceptable limits.

Abstract: A protective breathing mask comprises a face encircling mask body which is connected to a compressed gas line for the supply of compressed gas thereto. The mask includes an encircling rim portion which defines an air seal cavity and it is provided with a passage in the body or separated from the body which is connected to the compressed gas line for supplying gas into the seal cavity. The rim includes an inner lip which engages over the face of the wearer and the gas which is circulated to the cavity escapes between the lip and the face into the mask interior. The gas conduit advantageously includes a lung demand inlet valve which opens into the front or into one side of the mask and which has a by pass passage through a throttle to the seal cavity. The seal cavity is advantageously defined by an outwardly formed annular bead or by an annular tubular member which may for example have openings around its periphery for directing the compressed gas from the cavity into the mask interior.