Thermal time-delay switch
US4131930A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 1977 |
| Grant date | Dec 26, 1978 |
| Priority date | — |
| Expiry date | Apr 13, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H43/304
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A thermal time-delay switch comprises contacts which are normally engaged, a first bimetallic element associated with one of the contacts to separate the contacts from each other with temperature rise in the first bimetallic element, a second bimetallic element associated with the other of the contacts to bring the contacts into engagement with each other with a temperature rise in the second bimetallic element, and a heating resistor provided for each of the first and second bimetallic elements to heat it. The relative displacement between the contacts caused by the first bimetallic element with the temperature rise therein is larger than that caused by the second bimetallic element, so that the contacts are separated from each other substantially independent of voltage fluctuations over a wide range of a voltage source feeding the two heating resistors when the heating resistors have been connected to the voltage source for a given period of time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.