Circuit breaker having a cam structure which aids blow open operation
US5926081A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 23, 1997 |
| Grant date | Jul 20, 1999 |
| Priority date | — |
| Expiry date | Sep 23, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H2001/223
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit breaker includes a cam assembly which holds the load blade in contact with the line strap during normal operation. The cam assembly includes a cam surface on a cam which can slide along the load blade and a bearing surface on the load blade. In normal operation, the cam is biased on the load blade so that the cam surface engages the bearing surface. The force applied by the cam surface to the bearing surface in normal operation is approximately parallel to the force applied by the load blade to the line strap, thus, the cam surface does not tend to slide along the bearing surface during normal operation. When a high overcurrent fault occurs, blow-open forces exerted between the load blade and the line strap cause the cam to pivot to a position where the cam surface no longer engages the bearing surface, allowing the load blade to swing free of the cam and break the contact between the load blade and the line strap. As the load blade swings free of the cam, it engages a further cam surface of the cam which reduces the biasing force essentially to zero, thereby increasing the opening speed of the blade. In addition, the frictional force of the further cam surface against th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.