Microphone attenuation device for use in oxygen breathing masks

摘要

A microphone signal attenuating breathing mask body having a gas port for inhalation of a gas to the wearer in a flow stream therethrough. A demand microphone is mounted to the mask and is coupled to an electromagnetic switch responsive to a predetermined magnetic field for switching from an actuation to an attenuation position to block transmission of sound from the microphone. An air vane is pivotally mounted on the mask body and is formed with an impingement pad positioned in the flow stream and mounts an activating magnet disposed adjacent the switch. The vane is normally disposed in a normal position such that the magnet is in an activating position and the electromagnetic switch is in the actuation position such that the microphone is active for transmission of audio signals. Upon inhalation by the wearer, the vane is responsive to the impingement of the air stream on the impingement pad to move the vane to a displaced position moving the magnet to the deactivating position, switching the switch to the attenuation position to block transmission of audio signals from the microphone.