Pressure contact between ferrules and fusible element of electric fuses

Abstract

A solderless pressure contact between a cap or ferrule of a fuse and the end of a fusible element that has been bent around the rim of the casing of the fuse from the space inside the casing to the outer surface thereof. A normal ferrule is used, i.e. a ferrule having a planar end surface rather than one having an end surface projecting into the casing of the fuse. The side wall, or lateral wall, of the ferrule is provided with a tab being hingedly supported at the axially inner end thereof by the lateral wall of the ferrule. The aforementioned tab slants from its point of support by the lateral all of the ferrule, or from the axially inner end thereof, axially outwardly and radially inwardly into firm engagement with the end of the fusible element on the outer surface of the casing. This pressure contact requires the use of casings which are electically deformable according to Hooks law, or have a memory, i.e. tend to assume their original shape after having been deformed. The aforementioned single tab formed out of the lateral wall of a ferrule may be sectionalized into two sections. The tab, or its sections, engage the end of the fusible element located on the outer surface of the casing substantially linearly, thus producing an electric contact having a high contact pressure and a small contact resistance.