Electric incandescent lamp for series arrangement having an electrically conductive vitreous body connecting current-supply conductors

Abstract From the Canadian patent

The electric lamp for series arrangement comprises at least one current-supply wire (3) of nickel wire copper wire or copper, cladded wire. A shortcircuit switch (5) is provided which consists of a, vitreous mass (6) in which copper powder is dispersed and which is fused with the current-supply wires (3) and of an oxide skin (8), which, is present on the said current-supply wire at the sealing-in area in the mass (6). The vitreous mass (6) is electrically conducting. An electrical connection between the current-supply wires (3) is not obtained, however, until the filament (2) burns through and the oxide skin (8), breaks down due to the overvoltage then occurring.