Tone generator
US4286257A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1979 |
| Grant date | Aug 25, 1981 |
| Priority date | — |
| Expiry date | Dec 19, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B7/06
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A tone generator for producing an audible sound for a predetermined time period in response to the occurrence of one or more predetermined conditions. The tone generator comprises a diaphragm mounted within a resonant sound cavity that is activated by an electromagnetic assembly which is in turn driven by the output signal from an oscillator circuit. The control logic and timing circuit for the tone generator includes a unique PTC subassembly that provides a timed logic signal for controlling the activations of the diaphragm, as well as an independently generated signal for contemporaneously activating a lamp which provides a visual indication of the detected predetermined condition. The control logic and timing circuit is adapted to produce the proper timed logic signal despite the absence of a lamp in the circuit or a lamp failure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.