Acoustic alarm employing a resonant cavity arrangement

An alarm comprises a casing containing a cavity 16 with at least one opening 18. Within said cavity 16 is disposed an acoustic transducer 7 which is connected to drive means which is activated by switch means 44, 46, 48. The drive means, when activated, induces said acoustic transducer 7 to operate...

Full description

Saved in:
Bibliographic Details
Main Authors KEITH NUNNERLEY AITCHISON, CHRISTOPHER DAVID SHELTON
Format Patent
LanguageEnglish
Published 04.03.1998
Edition6
Subjects
ACOUSTICS
ACOUSTICS NOT OTHERWISE PROVIDED FOR
ALARM SYSTEMS
ELECTRONIC TIME-PIECES
HOROLOGY
METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING,NOISE OR OTHER ACOUSTIC WAVES IN GENERAL
MUSICAL INSTRUMENTS
ORDER TELEGRAPHS
PHYSICS
SIGNALLING
SIGNALLING OR CALLING SYSTEMS
SOUND-PRODUCING DEVICES
Online AccessGet full text

Cover

More Information
Summary:An alarm comprises a casing containing a cavity 16 with at least one opening 18. Within said cavity 16 is disposed an acoustic transducer 7 which is connected to drive means which is activated by switch means 44, 46, 48. The drive means, when activated, induces said acoustic transducer 7 to operate at a resonant frequency of said cavity 16. Resonant chambers or tubes 11 may be linked to the cavity 16. The alarm may be adapted to be worn on the wrist in combination with a time piece 5. The transducer 7 may comprise a Helmholtz resonator, diaphragm 22 and magnet material 32 arrangement or a piezoelectric device (see figure 7). The drive means may comprise a transformer and high-frequency pulse modulation circuitry.
Bibliography:Application Number: GB19960018241