Retrofitting gas mask voice amplifier unit with easily actuated switch means
US5224474A · kind A · utility
Inventor
Key dates
| Filing date | Jun 10, 1991 |
| Grant date | Jul 6, 1993 |
| Priority date | — |
| Expiry date | Jun 10, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R1/44
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An electrical amplifier unit which removably attaches to a gas mask and includes a separate microphone for detecting voice sounds emitted by the wearer of the gas mask, circuitry for amplifying the detecting sound, and a loudspeaker for emitting the amplified sounds externally of the mask. The associated components, except for the microphone, are contained within a housing which can be disassembled and which also contains a removable battery pack. The housing also is sealed from the external environment when completely assembled. The circuitry amplifies and filters the signals converted by the microphone and supplies a signal to the loudspeaker which is enhanced in the high frequency range but limited in the low frequency range so that the emitted sound is crisp and intelligible voice sounds. The microphone attaches over the mechanical emitter of the mask remote from the amplifier unit and is connected to an adaptor which mounts the amplifier unit onto the mask. The adaptor attaches to the noise piece of the mask without disturbing the structural integrity of the mask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.