Seismic trigger
US4214238A · kind A · utility
11Cited by
2References
10Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 8, 1977 |
| Grant date | Jul 22, 1980 |
| Priority date | — |
| Expiry date | Mar 8, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S200/08
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An inverted, compound pendulum, which may be set in motion by a seismic variance, activates a photoelectric switching system. Logic circuitry in electrical contact with the switching system discriminates in a pre-determined manner with respect to the repetition rate of signals transmitted by the switching system and selectively activates and controls an alarm. Circuitry in the device permits display of the device's status and interacts with a self-contained power source to permit continued operation despite interruption of external power.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.