Overload protector for a telephone set
US4661881A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 1984 |
| Grant date | Apr 28, 1987 |
| Priority date | — |
| Expiry date | Sep 17, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/176
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An overload protector for a telephone set or other telecommunications terminal comprises an electrical component having DC continuity and DC resistance mounted by leads on a circuit board, the leads soldered to the conductor pattern. On application of an overload, the component heats up to a level at which sufficient heat travels along the leads to melt the solder. Usually both leads become unsoldered. One or both leads part from the conductor pattern under the effect of gravity; under the effect of a compression spring on one or both leads and held in compression between component and circuit board; or a combination of both. A convenient component is a carbon block resistor, in the Tip or Ring line. A heat insulating member can be positioned around the component. The insulating member can be a sleeve loosely fitting over the resistor and retaining heat in the resistor, or a coating or layer directly on the component.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.