| 摘要 |
<p>An earthquake alarm (10) includes a housing (16) that can be mounted on a surface (12) and a cylindrical cantilever beam (98) mounted in the housing (16). A ferromagnetic element (114) is attached to the free end (102) of the beam (98), and an electrical coil (128) is disposed in the housing directly beneath the beam (98), in a surrounding relationship with the ferromagnetic element (114). Earthquake vibrations cause the cantilever beam (98) to vibrate, thereby moving the ferromagnetic element (114) in an oscillating pattern adjacent the coil (128). In response to the oscillating ferromagnetic element (114), the coil (128) generates a voltage signal that is representative of the presence of the earthquake. A signal processing system (134) is provided to amplify and condition the signal from the coil (128) and energize an audible alarm (52) and a warning lamp (54) when the frequency of the signal is in the range of 3-15 Hz.</p> |
