Miniature dual cavity ringer
US4728933A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 24, 1986 |
| Grant date | Mar 1, 1988 |
| Priority date | — |
| Expiry date | Mar 24, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10K9/12
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A ringer employs a low-cost miniature transducer, having a reverberant cavity, mounted in a cylindrical housing which has a second reverberant cavity in front of the miniature transducer. A very large acoustic output power is achieved when the ringer is employed in known cordless telephones, using the conventional available 3.9 volts battery. The ringer, due to its small relative size, may fit in the limited space inside a cordless telephone portable unit without costly tooling modifications. It is also suited for other uses, including for employment in compact one-piece telephones. The ringer is substantially more compact, louder in sound level, more pleasant sounding than known devices, and operates from a substantially lower DC voltage source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.