Retrofitting gas mask voice amplifier unit with easily actuated switch means
US5224473A · kind A · utility
Inventor
Key dates
| Filing date | Mar 4, 1991 |
| Grant date | Jul 6, 1993 |
| Priority date | — |
| Expiry date | Mar 4, 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 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 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 voice sound is crisp and intelligible. The amplifier unit is attachable to some gas masks without additional hardware and to others with a removable adaptor. In either case, the amplifier unit does not affect the structural and functional integrity of the host mask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.