Thermal control units
US4829280A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 28, 1987 |
| Grant date | May 9, 1989 |
| Priority date | — |
| Expiry date | Jul 28, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2037/5472
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An element protector control for protecting the electrically powered heating element of a kettle against overheating has primary and secondary (or back-up) modes of operation. The primary protection mode utilizes a dished, snap-acting bimetal which is oriented so that the side of the bimetal which is convex when the blade is cold faces the heating element head, and the bimetal is sprung against a flat rear surface of the element head so that the bimetal in its cold condition flattens against the element head. The bimetal determines the condition of a pair of switching contacts provided in the control. The bimetal is mounted in a carrier which is spring biassed towards the element head and, for providing the secondary protection mode, the carrier is formed of a thermoplastics material so that in the event of failure of the primary protection in an overtemperature situation so that the element temperature continues to rise, the carrier will collapse towards the element head, and the collapse of the carrier is arranged to disconnect the control from its power supply terminals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.