International Safety Instruments, Inc.

Robert E Gray

R David Lewis

Paul D Hiltman

Victor Speck

Bruce A Hefner

Donald W Dawson

A backframe for a self contained breathing apparatus (SCBA) is formed of a molded shell having some depth, and a closure plate fixed to the shell to provide an enclosed volume. The molded shell with the closure plate yields a good weight-to-strength ratio, and provides a water- and dust-resistant enclosure for control components of the SCBA. A water-tight battery compartment is enclosed within the shell so the batteries are separated from other components. A low air pressure alarm provides an auditory signal, and may also include a tactile signal. A buddy breathing hose can be pulled from the backframe to provide a reasonable length tether; and, by connecting two such buddy breathing hoses, twice the length is provided.

Combination backframe and self contained breathing apparatus

A self contained breathing apparatus has a display of air pressure within the face mask in the field of vision of the user of the breathing apparatus. The display is four lights that indicate the four quarter-tanks of pressure, and the lights change to indicate the amount of air remaining. A transducer receives tank pressure and provides an electric signal. The air pressure is placed on a bourdon tube which rotates a disk in response to changes in pressure. One half of the disk includes a gradient, and a light source emits light through the gradient to be received by a light sensor. As the disk rotates, the gradient varies the amount of light received by the sensor, so the electrical output of the sensor varies.

Pressure display for self contained breathing apparatus

A holder for a personal alert safety system (PASS) has a bracket to receive the PASS, and a housing connected to the bracket. An additional activation switch is installed in the PASS, the additional switch being magnetically operable. The housing is connected to the air line of a self contained breathing apparatus (SCBA). A piston or diaphragm is urged in one direction by air pressure, and is urged in the opposite direction by a spring in the absence of air under pressure. When the piston is moved in the one direction, a magnet is disposed adjacent to the additional switch, and when the piston is moved in the opposite direction by the spring, the magnet is removed from adjacent to the additional switch so the PASS is automatically activated by the presence of air pressure in an activated SCBA. The PASS can be used without the SCBA and can be activated manually as is conventional, either attached to or removed from the SCBA.

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Lawrenceville, GA, United States of America

Robert E Gray