Fast acting thermal relay
US4184136A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1978 |
| Grant date | Jan 15, 1980 |
| Priority date | — |
| Expiry date | Feb 16, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H61/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A snap-action thermal relay in which a thin sheet of spring material having a central opening is mounted at one point along one edge and is crimped along an adjacent edge to distort the sheet into a slightly convex bowed shape. A heater element in the form of a thin band of metal is anchored at either end to the normally convex surface of the sheet adjacent opposite edges of the sheet, with a bridging member inserted between the band and the sheet to put the band under tension. A printed circuit heating element is applied to the band on the side opposite from the sheet. The tension in the band holds the sheet in a concave bowed condition. Heating of the bank reduces the tension in the band and allows the sheet to snap back to its normal convex bowed condition. This action brings the band into direct thermal contact with the convex surface of the sheet over a substantial length of the band to provide good conductive transfer of heat from the band and heater to the spring sheet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.