Non acoustic alarm device
US6563422B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 21, 2001 |
| Grant date | May 13, 2003 |
| Priority date | — |
| Expiry date | Sep 21, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B6/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention concerns a non acoustic alarm device, intended to be fitted to a unit worn in contact with the body, such as a timepiece or a portable telephone, including a case, a moving mass within said case intended to transmit vibrations thereto, a coil (L) electromagnetically coupled to said moving mass to cause it to oscillate, and an excitation circuit of said coil. According to the invention, the device includes means for measuring the instantaneous oscillation frequency of the coil-moving mass unit during the oscillation in progress, as well as means for generating a series of excitation pulses for said coil during the following oscillation, whose characteristics are a function of the measurement of said instantaneous oscillation frequency. Due to its high yield and low energy consumption, this device is particularly suitable for watches.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.