| 摘要 |
A filament switching device is arranged to be mounted within the screw base of a conventional, dual-filament, incandescent light bulb. The device has a frame which branches around the evacuation tube of the bulb thereby allowing sufficient room for switching components within the device and yet avoiding interference with the evacuation tube of the bulb. Mounted within the frame of the switching device is a fixed contact and a cantilevered contact. The cantilevered contact can swing in a direction transverse to the evacuation tube to make electrical contact with the fixed contact. The cantilevered contact is held separated from the fixed contact by a fusible conductor. Upon failure of one of the filaments in the bulb, a surge of current flows through the fusible conductor, parting it and allowing the cantilevered contact to swing into electrical contact with the fixed contact. This swing of the cantilevered contact substitutes the failed filament with the other filament.
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